Rewilding Weeloo, the Enigmatic Bush Stone-curlew

Cold wind buffets my breath as the small boat bounces along the waves. We are heading towards a tiny, sun-bleached rocky nub of an island, one of the many that cluster about the sprawling, inverted triangle of Eyre Peninsula, like small fish shadowing a large, cruising shark. And sharks aren’t far from my mind. As I clamber from the boat to the sloping brown rocks, slick with algae, I’m concentrating hard on not falling in. Great white sharks are regulars in these waters – they take fish, seals, sea lions and the occasional unfortunate surfer or abalone diver. Right now the Australian sea lions are pupping, which is why I am here on this island. I’m helping researchers Peter Shaughnessy and Terry Dennis count this season’s pups to help track the status of this threatened species.

The Australian sea lion is golden-coated, dewy-eyed and the only pinniped that’s endemic to Australia. The lithe, sleek females are reclining here and there, dozing in the bright sunlight. Their chocolate-brown pups are less obvious and more difficult to find. We scramble transects across the low rocky brow of the island, keeping each other in sight to make sure no pups are missed.

Illustration by Paula Peeters

Eyre Peninsula is about halfway along the southern shoreline of Australia, and a special cast of creatures inhabit its coasts and islands. Dapper black-and-white pacific gulls stand sentinel on rocks and beaches, often in pairs. Green rock parrots tinkle as they alight daintily on the coastal bushes, gleaning puckered yellow berries from the ruby saltbush. They chatter to each other, inspecting cracks and crevices in the cliff lines for possible nest sites. Oystercatchers pipe sadly as they fly parallel to the beach, in pairs, and white-bellied sea eagles and ospreys can often be seen drifting high overhead. Some islands have bilbies, others have bettongs, rock wallabies, or stick-nest rats. There are also ark populations of pythons, and odd varieties of tiger snake.

Today, the matronly bulk of gentle grey Cape Barren geese are surveying us warily, red eyes alert behind zinc-yellow beaks. As I carefully examine the bony carapace of the island in my search for sea lion pups, my eyes occasionally sink into the unfocused depths of a downy goose nest. Its softness contrasts strangely with the harshness of the low spiky, salt-pruned bushes and the sparse threads of dry grass. And suddenly, glaring at me with its enormous yellow eyes, is a bush stone-curlew. Upright and obvious on its long, thin legs; slight and seemingly vulnerable against the wide sky.

Sea-lion, goose and stone-curlew, assembled on this low treeless island surrounded by sea – a striking image, and one that challenges my idea of the ‘normal’ habitat of a bush stone-curlew. I had associated this enigmatic, ground-dwelling bird with grassy woodlands, not rocky, sea-swept islands. But I am so happy to see it here, slowly sidling away, neck extended, its buff-and-brown markings already dissolving back into the landscape. The bush stone-curlew Burhinus grallarius – also known as the bush thick-knee – has declined over large parts of it range, including throughout Eyre Peninsula. It’s one of the threatened species we are trying to restore to Coffin Bay National Park, a mainland park that is not far away. Stone-curlews are described as ‘terrestrial waders’, and there are 10 species worldwide. But the bush stone-curlew is more closely associated with dry land than wetlands. Before European settlement it was found over much of the Australian mainland, but it is now listed as threatened in the south-eastern states of Victoria and New South Wales.

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The barren calcrete landscape is illuminated in the headlights as K.D. Lang’s rich, languid voice fills the cab of the 4WD. Perhaps incongrously, but then perhaps there is a likeness between this landscape and the mid-winter bleakness of the lands of the 49th parallel. Nothing stirs as our 4WD lurches after ranger Tom’s ute, which is showing us the way over this seemingly blasted landscape of bare white rocks, twists of grazed-down grasses, and the bleached gnarled bodies of sheoaks, laying sideways where they once stood tall. Stubborn clumps of half green, half twiggy-dead coast beard-heath and other unpalatable shrubs loom in and out of view. And every now and then there is a movement – the rhythmic bounce of a western grey kangaroo – and then it stops and stands, turns to look towards us, into the headlights. Quizzical, and not very smart. An easy target if we had a gun, but we don’t. Tom Gerschwitz isn’t hunting roos tonight – the cull will be later in the year. Tonight we’re hunting bush stone-curlews, but not to kill. They’re a cherished native species, and part of the ecological restoration of this park. Tonight we’re trying call-playback to find out if they have returned.
The call of a bush stone-curlew is an unearthly, haunting thing. It begins as a weird wail that swells in volume and rises in tone, and then multiplies into a shuddering cacophony of hysterical cries. It sounds like many birds are calling, but I’m told it only emanates from one. But bush stone-curlews often call together – in gatherings that have been described as whistling concerts, corroborees or glee parties. In many Aboriginal cultures the stone-curlew’s call is associated with death. The Warlpiri people of the Tanami Desert believe that when a stone curlew calls in a certain way then there are many dingoes around; if it calls differently a small child might throw a trembling fit. Aboriginal names for these birds include Weeloo and Willaroo – which echo the sound of its call – and also Wayayi, Wirntiki and Ngamirlirli. No doubt there are many more Aboriginal names, since the bush stone-curlew’s natural range is most of mainland Australia.

We cut the gurgling diesel engines and are swallowed by the dark stillness of the night. Except for the distant sigh of the sea, in place of the sighing that the wind would have made in the sheoaks, were they still alive. Tom knows from old folk’s tales and surveyors’ maps that this place was a sheoak grassy woodland when white people settled here. The drooping sheoak Allocasuarina verticillata is a graceful greyish tree with fine long hanging branchlets that look soft and hairlike from a distance, like the tails of the feral horses only recently removed from the Park. The Ngarrindjeri aboriginal people believe that the sound of wind in the sheoaks are the voices of their spirit ancestors. These trees are drought-tolerant and nitrogen-fixing; nutritious and highly palatable to horse, sheep, cow and rabbit. The early settlers introduced all four, which competed with the kangaroos that also like eating sheoaks. Any sheoaks that were within browsing height were devoured, and old trees were felled to provide extra feed. Fire and rain loosened the thin precious topsoil – already bared of grass from overgrazing, and the long, dry Mediterranean-climate summers. The soil washed away, exposing the calcrete bones of the Coffin Bay Peninsula. They made it a National Park when it wasn’t good for much else: Coffin Bay National Park, on the south-western tip of Eyre Peninsula.

In the darkness Tom plays the recorded wailing call of the bush stone-curlew. And we wait quietly, our breath steaming in the cold starlight. There is no answer from bird or beast, so we move on to the next monitoring site. And the next. No calls respond to the recorded cries. There are no stone-curlews here.

* * *

Several years have passed, and I now live in Brisbane, subtropical Queensland, many miles northeast of the Eyre Peninsula. I often cycle to the Queensland Herbarium, nestled in the foothills of Mt Coot-tha Forest, on the grounds of the Brisbane Botanic Gardens. The last steep slope up to the back entrance of the Herbarium takes some effort, especially at the end of a long ride. One day, when I was slowly pedalling up this bitumen driveway, I felt those yellow eyes upon me once more. This time there were two pairs of eyes: two bush stone-curlews were sitting blithely on the verge of the road. One standing, one sitting; both eyeing me calmly from their chosen resting place that was in the open, amongst the bark-chip-mulch.

This is a resident pair that is often seen around the back of the Herbarium, seemingly oblivious to the comings and goings of botanists and ecologists, and the loading and unloading of vehicles. Bush stone-curlews may be threatened in most of south-eastern Australia, but they are still secure in northern Australia, including Queensland. Even in the suburbs of Brisbane – which is a major city – there are many places where the wailing cry of the bush stone-curlew is often heard. This made me curious, as foxes were often cited in southern Australia as a major cause of the bush stone-curlew’s decline. But foxes are present in Brisbane, along with dogs and cats.

As an ecologist, I’m always wary of the simple answer. Most ecosystems are composed of numerous species, interacting in a multitude of complex ways, in space and time. I am also suspicious of certain people that seem to gain satisfaction from killing feral animals, and are eager to vilify these creatures, and blame them for the decline of native species. I suspect it’s some sort of displaced guilt. Over the last 200 years or so, humans (and the domestic animals we nurture) have been by far the most destructive feral animals that have impacted on the Australian environment. But instead of facing this reality, there is much hatred directed towards feral cats, foxes and rabbits.

Sheoak restoration within grazing enclosure.

Feral animals are a significant threat to many native Australian species. But sometimes feral species are not the main threat to a native species, or even a threat at all. The main factors that seem to have caused the decline of the bush stone-curlew in south-eastern Australia are the destruction of its habitat by overgrazing, burning and intensive clearing of vegetation. Tom understood this for Coffin Bay National Park – that the stone-curlews were unlikely to return without the restoration of the sheoak grassy woodlands, despite an ongoing fox control program. I suspect that the long dry summers and generally lower productivity of southern Australia also make it much harder to restore some habitats and maintain healthy populations of certain native species. In the parts of northern Australia where the bush stone-curlew is secure, even common, the summers are hot and wet, and the winters are mild. Plant growth is rampant, which results in a large and continuous supply of leaf-litter and woody debris, which are used by stone-curlews as breeding, resting and feeding sites. Heat, moisture and abundant plantlife also results in high numbers of insects, other invertebrates, frogs and lizards which make up the bulk of the stone-curlew diet. As long as some native vegetation is retained, fires are infrequent and grazing pressure is low (as is the case in the more leafy suburbs of Brisbane) it seems that bush stone-curlew habitat is in reasonably good supply, and these birds continue to survive, and even thrive. Even in the presence of the foxes, dogs, cats – and people – who also live in the greater Brisbane area.

* * *

In Coffin Bay National Park, and elsewhere on Eyre Peninsula, people are trying to coax sheoaks and native grasses back into the landscape, and in this way conserve the native species that rely on sheoak grassy woodlands. (In Australia, the term ‘woodland’ is used for a treed ecosystem where the trees are relatively widely spaced, and the foliage cover of the tallest tree layer is less than 30%. The term ‘forest’ is reserved for denser stands of trees where foliage cover of the tallest tree
layer is greater than 30%.) Woodlands with an open, grassy understorey have been heavily exploited for grazing and cropping. It’s no coincidence that many native plant and animal species that once lived in these grassy woodlands – especially those in southern Australia – are now in decline or are gone forever. As I learnt from my island adventure, the bush stone-curlew doesn’t always live in woodlands – it has a preference for open area generally, and has been observed nesting where there is good visibility at ground level for at least 250 m all round. But in many mainland habitats the bush stone-curlew is strongly associated with leaf litter and woody debris. These provide good camouflage for the stone-curlew and also homes for the small creatures that it hunts. Fires, grazing, tree loss, firewood collection and just general ‘tidying up’ all result in less leaf litter and woody debris. Fortunately, people are learning that an ‘untidy’ woodland – where wood and litter are left where they fall – provides a much healthier habitat for wildlife than one that is regularly groomed, and devoid of organic clutter.

Bush Stone Curlew – image by Raymond Carpenter

In southern New South Wales the Nature Conservation Working Group has been releasing captive-bred bush stone-curlews to supplement the dwindling local populations of this species. There have been six releases since 2008. Most of the birds have survived and some have also bred, with the most recent chicks sighted in January 2015. Predator control is an important part of the rewilding of the bush stone-curlew, but it isn’t the only factor involved. A release of bush stone-curlews into a predator-free enclosure in New South Wales was less successful (in terms of bird survival) compared to a concurrent release of birds into a predator-controlled, unfenced area nearby. The Australian Wildlife Conservancy, which manages these sites, suggested that starvation was the cause of bird mortality in the predator-free area. Research by Elisa Tack in southern New South Wales and north east Victoria has also revealed the important, but often overlooked role of food availability for the conservation and rewilding of the bush stone-curlew.

Bush stone-curlew romance, or at least sex, has also made it to the internet, thanks to an innovative rewilding project in the Australian Capital Territory. The Mulligans Flat Woodland Sanctuary has reintroduced a number of locally extinct woodland animals – including the bush stone-curlew – into a predator-free enclosure which adjoins a new suburb. By law, neighbouring residents are required to keep their cats on their premises at all times. A bird called Rowena was part of the first group of bush stone-curlews released in October 2014. Like many young adolescents she was keen to explore the world on her own terms, and promptly flew out of the predator-free enclosure to try a bit of urban living. Fortunately she survived some brief forays across roads, and some cat-naps on road verges and roundabouts, and was returned by concerned residents when they noticed her leg tag. Since then she has stayed within the predator-free Sanctuary, and has developed an attachment to fellow-release bird Herbie. Both were captured on film while trying to procreate and you can watch their tentative dance on YouTube (https://youtu.be/YxXbqYZ5v-c ). Kate Grarock, the ecologist at Mulligans Flat, thinks it’s unlikely that they will breed successfully for several months, but there is great excitement for the future. A second release of bush stone-curlews is planned for September/October 2015, and the local community appears to be enthusiastically behind the project.

The bush stone-curlew is a curious, charismatic, and some might say spooky part of Australia’s heritage. Many people across the country are concerned for its welfare, and are working hard to ensure the continued existence of this species. Our understanding of wildlife ecology is also maturing, as more and more people comprehend the complexity of ecological interactions, and the importance of good quality habitat as well as predator control when it comes to saving threatened species. Whether these efforts can keep up with the rapacious rate of ongoing environmental degradation, especially the impacts of a continuously growing human population, and the ongoing effects of climate change, is not known. But at least the bush stone-curlew has many friends, and the rewilding movement just keeps on growing.

* Update on the Mulligan’s Flat stone-curlews, December 2015: Rowena and Herbie are still living within the Sanctuary, and have raised their first chick. The chick is doing well, and is seen on camera each week. Ten more captive-bred bush stone-curlews were released into the Sanctuary in October 2015, and all have survived so far. Just before Christmas two of the newly-released birds (Lewis and Kay) were found to be protecting a nest with eggs, much to the delight of everyone involved in Mulligan’s Flat.

References and thanks

Anderson, G.J. (1991) The breeding biology and the bush thick-knee Burhinus magnirostris and notes on its distribution in the Brisbane area. The Sunbird 21:32-61

Tack, E. (2014) Lessons from 10 years of Studying Bush Stone-curlews. Abstract for the 3rd Curlew Summit, August 2014, Albury.

Paula Peeters is a writer, artist and ecologist. Her written work ranges from playful observations of nature, to science communication, and many things in between. Her art practice focusses on wildlife and ecosystems, and strives to capture the beauty, habit and characteristic light of these subjects. Paula blogs at www.paperbarkwriter.com